Supported ruthenium catalysts utilizing a solvent system have provided generally effective hydrogenation of olefinically unsaturated dinitriles.
Unfortunately, these supported ruthenium catalysts in practice have had a relatively short run life, and have proven very difficult to regenerate. In fact, upon fouling or deactivation, the supported catalyst usually has been simply dumped from the contactor and returned to the manufacturer for reclaiming of the valuable ruthenium. Not only is this a material-costly procedure, but short run life means more frequent down times, and the handling of the catalyst means a labor cost intensive operation despite the theoretically efficiency of the hydrogenation process when it is running satisfactorily.
Badly needed has been method to extend the run life, useful catalyst life, of the supported ruthenium catalyst in the hydrogenation of olefinically unsaturated dinitriles.